Method and apparatus for determining stone cells in paper or pulp

(19)

(11)

EP 1 279 947 A3

(12)	EUROPEAN PATENT APPLICATION

(88)	Date of publication A3:
	10.03.2004 Bulletin 2004/11

(43)	Date of publication A2:
	29.01.2003 Bulletin 2003/05

(21)	Application number: 02405650.9

(22)	Date of filing: 26.07.2002

(51)	International Patent Classification (IPC)⁷: G01N 21/64

(84)	Designated Contracting States:
	AT BE BG CH CY CZ DE DK EE ES FI FR GB GR IE IT LI LU MC NL PT SE SK TR
	Designated Extension States:
	AL LT LV MK RO SI

(30)

Priority:

26.07.2001 CA 2354202

(71)	Applicant: Alberta Research Council, Inc.
	Edmonton, Alberta T6N 1E4 (CA)

(72)	Inventors:
	Henry, Deborah Jean Sherwood Park, Alberta T8A 1C9 (CA) Chow, Ross S. Sherwood Park, Alberta T8A 1C9 (CA) Yuan, Hongqi Edmonton, Alberta T5T 6B6 (CA)

(74)	Representative: Frei, Alexandra Sarah
	Frei Patentanwaltsbüro, Postfach 768 8029 Zürich 8029 Zürich (CH)

(54)	Method and apparatus for determining stone cells in paper or pulp

(57) Disclosed is a method and apparatus for determining stone cells within a sample of wood pulp or paper. According to the instant invention a portion of the sample is irradiated with light at a predetermined wavelength or within a predetermined range of wavelengths. The incident light causes those areas of the sample that are occupied by stone cells to fluoresce strongly relative to the background matrix of wood pulp or paper. The strongly fluorescing stone cells are registered digitally using a detector, or are observed visually by an operator viewing the sample through an ocular device. The absolute number of stone cells per unit area or a stone cell size-distribution-plot is obtained using one of automated or manual image analysis.

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